Heritability of specific cognitive functions and associations with schizophrenia spectrum disorders using CANTAB: a nation-wide twin study.

Background: Many cognitive functions are under strong genetic control and twin studies have demonstrated genetic overlap between some aspects of cognition and schizophrenia. How the genetic relationship between specific cognitive functions and schizophrenia is influenced by IQ is currently unknown.

Methods: We applied selected tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) to examine the heritability of specific cognitive functions and associations with schizophrenia liability.

Low frontal serotonin 2A receptor binding is a state marker for schizophrenia?

Here we imaged serotonin 2A receptor (5-HT2AR) binding in a very rare population of monozygotic twins discordant for schizophrenia to provide insight into trait and state components in brain 5-HT2AR patterns. In four twin pairs not medicated with drugs that target 5-HT2AR, frontal 5-HT2AR binding was consistently lower (33%) in schizophrenic- relative to their healthy co-twins. Our results strongly imply low frontal 5-HT2AR availability as a state feature of schizophrenia.

Course of intelligence deficits in early onset, first episode schizophrenia: a controlled, 5-year longitudinal study.

Only few prospective longitudinal studies have assessed the course of intelligence deficits in early onset schizophrenia (EOS), and these have used different age appropriate versions of Wechsler Intelligence Scales and age appropriate norms. The post-psychotic development of intelligence in EOS has predominantly been characterized as relatively stable in these studies. However, comparisons of IQs from different test versions based on the different norms may not permit unequivocal interpretations.